CA3228996A1 - Suspension control system - Google Patents

Abstract

A system and method for controlling the suspension of a vehicle. The method comprises providing in each suspension assembly, a suspension actuator spanning between the wheel and the body, measuring an angle of the body along at least one axis thereof relative to horizontal and measuring an extension of each suspension actuator. The method further comprises utilizing a processor, determining an articulation target for the vehicle, determining a body angle target for the vehicle, determining a suspension actuator travel limit for each corner of the vehicle and determining a ride height in each corner of the vehicle from a predetermined prioritization of a plurality of criteria comprising articulation target, body angle target and suspension actuator travel limit. The method further comprises causing each suspension actuator to move to the determined ride height.

Description

SUSPENSION CONTROL SYSTEM
BACKGROUND
1. Technical Field This disclosure relates generally to methods and systems for controlling the suspension of a vehicle and in particular to methods and systems for controlling the movement of a body of the vehicle.

2. Description of Related Art Many vehicles encounter obstacles which may upset the orientation of the vehicle or interrupt the contact of one or more wheels of the vehicle on the ground. Such obstacles are commonly encountered in off road or other environments where previous conditioning of the ground surface has not been performed. Such obstacles may include, but not limited to, rocks, logs, ledges or other bodies. Other obstacles may comprise the ground surface itself which may be significantly non-level including ledges, drops, steep inclines and the like. Over such obstacles, conventional vehicles have struggled to both navigate the chosen path while also maintaining the occupants in a degree of comfort and minimizing damage to the ground surface.
In particular, conventional wheeled vehicles utilize a spring and shock absorber to support the vehicle on each of the wheels proximate to corners of the vehicle. When a particular obstacle each wheel will be permitted to move by compressing the spring in accordance with the spring constant of that spring. It will be appreciated that in cases where the obstacle encountering wheel is lifted relative to the other wheels by the obstacle, this will in turn also increase the pressure applied by that wheel to the obstacle as dictated by the spring constant of that wheel. It will be appreciated that such increased ground pressure may be undesirable on soft or sensitive ground.
Furthermore, it will be appreciated that the resulting decreased ground pressure on the unloaded wheels may result in a reduction in traction at that wheel which may then result in wheel spin at that tire causing further ground damage.
387ja 174 1/E1U4rUg d 2024-02-13 In addition, conventional vehicles when traversing a non-level ground surface will have the body of the vehicle oriented to an angle corresponding to the angle of the ground. It will be appreciated that some such angles may be uncomfortable for a vehicle occupant and increase the risk of rollover. In addition due to the above need to provide for a higher length of upward wheel travel to avoid obstacles, many off road vehicles will include bodies lifted above the wheels to provide such increased wheel travel. Unfortunately, such increased lift also exacerbates the effects of any ground angle on the vehicle which may make the vehicle more at risk to roll over conditions.
SUMMARY OF THE DISCLOSURE
According to a further embodiment of the present disclosure there is disclosed a method for controlling the suspension of a vehicle, the vehicle having a body and a wheel proximate to each corner of the body suspended from the vehicle by a suspension assembly. The method comprises providing in each suspension assembly, a suspension actuator spanning between the wheel and the body, measuring an angle of the body along at least one axis thereof relative to horizontal and measuring an extension of each suspension actuator. The method further comprises utilizing a processor, determining an articulation target for the vehicle, determining a body angle target for the vehicle, determining a suspension actuator travel limit for each corner of the vehicle and determining a ride height in each corner of the vehicle from a predetermined prioritization of a plurality of criteria comprising articulation target, body angle target and suspension actuator travel limit. The method further comprises causing each suspension actuator to move to the determined ride height.
The articulation target may be looked up on a predefined chart or graph defining a predefined articulation bias. The predefined articulation bias may be reduced relative to a 1 to 1 ratio within a predefined angle zero. Each actuator may comprise a cylinder including a piston therein defining a top chamber above the piston and a bottom chamber below the piston wherein 387ja 174 1/E1U4rUg d 2024-02-13

-3-the vehicle further includes a pressurized fluid source in selective communication with each of the top and bottom chambers. The method may further comprise adding or removing fluid from one or more top or bottom chamber of one or more pistons as determined by the processor.
The method may further comprise determining a ready state of the each actuator, receiving a desired suspension stiffness target and utilizing the processor, calculating the actuator target states to provide the determined ride height and spring rates;
The ready state comprises the pressure in one or more of the top and bottom chambers and accumulators of a suspension cylinder and adjusting pressure within each cylinder and/or accumulator to maintain achieve the desired ride height and suspension stiffness. The suspension stiffness target may be variable.
The prioritization may comprise satisfying each criteria in a predefined order until satisfaction is not possible. The prioritization may comprise satisfying each criteria in a predetermined ratio. The processor may determine a measurement of the ground slope using the measure of the body angle and the measurement of each suspension actuator extension. The processor may determine the body angle target from the ground slope.
According to a further embodiment of the present disclosure there is disclosed a system for controlling body position of a vehicle comprising a suspension assembly at each corner of the vehicle having a suspension height actuator, a processor in communication with each suspension height actuator and a memory. The memory containing instructions which when executed by the processor determine an articulation target for the vehicle, determine a body angle target for the vehicle, determine a suspension actuator travel limit for each corner of the vehicle and determine a ride height in each corner of the vehicle from a predetermined prioritization of a plurality of criteria comprising articulation target, body angle target and suspension actuator travel limit.
The 387ja 174 1/E1U4rUg d 2024-02-13

-4-processor causing each suspension height actuator to move to the determined ride height.
The system further comprise at least body angle sensor operable to transmit to the processor a measurement of the angle of the body along an axis relative to a horizontal plane. The system further comprise a position sensor configured to measure the position of each suspension height actuator.
According to a further embodiment of the present disclosure there is disclosed a suspension assembly for a vehicle comprising a wheel assembly located proximate to each corner of the vehicle, a suspension actuator extending between each wheel assembly and the vehicle, the suspension actuator operable to support the vehicle thereon and a processor operable to provide instructions to a valve assembly between the fluid source and each cylinder wherein the processor is configured to determine a desired vehicle body angle from a predetermined prioritization of body angle measurement, suspension articulation and ride height targets.
The suspension actuator may comprise a cylinder operable to support the vehicle thereon, each cylinder including a piston therein defining a top chamber above the piston and a bottom chamber below the piston. The suspension assembly may further comprise a fluid source operable to provide a pressurized fluid to at least one of the top or bottom chamber of at least one of the cylinders; and According to a further embodiment of the present disclosure there is disclosed a method for controlling body position of a vehicle comprising measuring a current angle of the vehicle using a body angle sensor, determining a distance of remaining compression at each of a suspension cylinder located at each corner of the vehicle, identifying a cylinder located at an uphill location on the vehicle and permitting the uphill cylinder to shorten until a remaining compression reaches a predetermined value or the current angle reaches a desired value.
387ja 174 1/E1U4rUg d 2024-02-13

-5-The method may further comprise lengthening a cylinder at an opposite corner of the vehicle to the uphill cylinder after the remaining compression in the uphill cylinder reaches the predetermined value if the current angle has not reached the desired value. The cylinders may comprise a fluid filled top chamber above a piston within the cylinder and a bottom chamber below the piston. The method may further comprise providing a fluid source operable to add or remove fluid from the top or bottom chambers According to a further embodiment of the present disclosure there is disclosed a method of controlling a suspension of a vehicle comprising providing a cylinder at corner of the vehicle suspending a wheel assembly therefrom, wherein the cylinder includes a piston therein defining a top chamber having a top chamber defining a top spring constant and a bottom chamber having a bottom spring rate defining a bottom spring constant and dynamically adding or removing fluid to one or more top or bottom cylinders so as to adjust one or more of spring rate, compression and rebound.
The method may further comprise a processor adapted to cause a fluid source to introduce or remove fluid from the top or bottom chamber to achieve the desired spring rate, compression or rebound. The processor may include a plurality of predetermined spring rates, ride heights, compression and rebound settings for a particular road condition.
Other aspects and features of the present disclosure will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings constitute part of the disclosure. Each drawing illustrates exemplary aspects wherein similar characters of reference denote corresponding parts in each view, 387ja 174 1/E1U4rUg d 2024-02-13

-6-Figure 1 is an illustration of a vehicle having a suspension control system therein.
Figure 2 is a cutaway view of a cylinder for use in the vehicle of Figure 1.
Figure 3 is a schematic of the suspension control system of the vehicle o Figure 1.
Figure 4 is an illustration of the suspension control system of the vehicle o Figure 1.
Figure 5 is a flow chart of the process for controlling the suspension of the vehicle of Figure 1.
Figure 6 is an illustration of a vehicle at a reoriented position on the angled surface.
Figure 7 is a graph illustrating an angular adjustment for the vehicle of Figure 1 on an angled surface.
Figure 8 is a graph of an exemplary relationship between ground angle and the suspension roll bias of the vehicle of Figure 1.
Figure 9 is a graph of an exemplary relationship between measured articulation bias and target articulation bias of the vehicle of Figure 1.
DETAILED DESCRIPTION
Aspects of the present disclosure are now described with reference to exemplary apparatuses, methods and systems. Referring to Figure 1, a vehicle having a suspension and suspension control system according to a first embodiment is shown generally at 10. The vehicle 10 may comprise a truck or other wheeled vehicle and may commonly include 4 wheel assemblies 12 including a wheel 14 at each corner. Each wheel assembly includes a wheel hub, brake and other associated components as are commonly known and is suspended from the body 8 of the vehicle by a suspension cylinder 20. Although a hydrodynamic cylinder 20 is illustrated, it will be appreciated that other suspension actuator types, including pneumatic, fluid, electromagnetic or the like may also be utilized.
387ja I 74 8i 1/15"L'd4rUg d 2024-02-13

-7-With reference to Figure 2, each cylinder 20 comprises an elongate outer body 22 extending between top and bottom ends, 24 and 26, respectively.
The top end 24 includes a mount for securing to the vehicle 10. The bottom end includes a lower rod 30 received therein. The lower rod 30 extends between top and bottom ends, 32 and 34, respectively wherein the bottom end includes a wheel assembly mount 36 for securing to a wheel assembly as is commonly known. The outer body 22 is substantially hollow wherein the top end 32 of the rod includes a piston 38 thereon dividing the cylinder into a top chamber 40 and a lower chamber 42. The top and bottom chambers 40 and 42 are substantially sealed with the exemption of pressurizing lines 44 extending thereto from one or more top and bottom accumulators 41 and 43, respectively and as are commonly known as illustrated in Figure 2. Although the accumulators are illustrated as separate in Figure 2, it will be appreciated that they may be part of the cylinder 20 as is commonly known.
As shown in in Figure 2, each pressurizing line 44 is operably connected through a valve 46 to a pressurized fluid source 47. In operation, the valve assembly is operable to supply or release fluid from each top or bottom chamber individually as determined by a processor 50.
Turning now to Figure 3, the vehicle 10 includes the processor 50, and memory 52 that stores machine instructions that, when executed by the processor 50, cause the processor 50 to perform one or more of the operations and methods described herein. The memory 52 may be of any known type including a cache memory unit for temporary local storage of instructions, data, or computer addresses. The vehicle 10 may further include display 54 for displaying one or more operating condition to a user and input 56 for receiving and displaying inputs from the user including, without limitation selecting driving mode.
The vehicle 10 further includes at least one body angle position sensor 58 operable to sense the angular orientation of the vehicle and one or more pressure 62 within each cylinder and/or position sensors 60 on the cylinders or other suspension components operable to indicate the angle or position of each 387ja I 74 8i1/15"L'd4rUg d 2024-02-13

-8-suspension assembly. In particular, the position sensors 60 may comprise angle sensors located on one or more of the suspension links. Non-limiting examples of the position and pressure sensors may be selected from any known or appropriate sensors including without limitation hall effect or capacitive non-contact position sensors. The vehicle 10 further comprises one or more pumps 64 for moving an actuating fluid throughout the system of Figure 3 in response to instructions from the processor 50 and one or more valves 66 for controlling such fluid flow.
More generally, in this specification, the term "processor" is intended to broadly encompass any type of device or combination of devices capable of performing the functions described herein, including (without limitation) other types of microprocessors, microcontrollers, other integrated circuits, other types of circuits or combinations of circuits, logic gates or gate arrays, or programmable devices of any sort, for example, either alone or in combination with other such devices located at the same location or remotely from each other. Additional types of processor(s) will be apparent to those ordinarily skilled in the art upon review of this specification, and substitution of any such other types of processor(s) is considered not to depart from the scope of the present invention as defined herein. In various embodiments, the processor 50 can be implemented as a single-chip, multiple chips and/or other electrical components including one or more integrated circuits and printed circuit boards.
Computer code comprising instructions for the processor(s) to carry out the various embodiments, aspects, features, etc. of the present disclosure may reside in the memory 52. The code may be broken into separate routines, products, etc. to carry forth specific steps disclosed herein. In various embodiments, the processor 50 can be implemented as a single-chip, multiple chips and/or other electrical components including one or more integrated circuits and printed circuit boards. The processor 50 together with a suitable operating system may operate to execute instructions in the form of computer code and produce and use data. By way of example and not by way of limitation, the operating system may be any suitable type including, without 387ja 174 1/E1U4rUg d 2024-02-13

-9-limitation, proprietary vehicle specific software, Windows-based, Mac-based, or Unix or Linux-based, among other suitable operating systems. Operating systems are generally well known and will not be described in further detail here.
Memory 52 may include various tangible, non-transitory computer-readable media including Read-Only Memory (ROM) and/or Random-Access Memory (RAM). As is well known in the art, ROM acts to transfer data and instructions uni-directionally to the processor 50, and RAM is used typically to transfer data and instructions in a bi-directional manner. In the various embodiments disclosed herein, RAM includes computer program instructions that when executed by the processor 50 cause the processor 50 to execute the program instructions described in greater detail below. More generally, the term "memory" as used herein encompasses one or more storage mediums and generally provides a place to store computer code (e.g., software and/or firmware) and data. It may comprise, for example, electronic, optical, magnetic, or any other storage or transmission device capable of providing the processor 50 with program instructions. Memory 52 may further include a floppy disk, CD-ROM, DVD, magnetic disk, memory chip, ASIC, FPGA, EEPROM, EPROM, flash memory, optical media, or any other suitable memory from which processor 50 can read instructions in computer programming languages.
Turning now to Figure 5, the processor 50 may measure the angle of the body of the vehicle 10 using the body angle sensors 58 in step 100. It will be appreciated that any known means for measuring the angular position of the vehicle 10 may be utilized, such as by way of non-limiting example an attitude and heading reference system. The processor 50 furthermore is adapted to receive a positon measurement from each corner through the suspension arm sensors 60 and/or cylinder position sensors 62. The processor then utilizes the body angle measurement and the measurements of the lengths of each cylinder 30 to calculate the angle of the ground under the vehicle. It will be appreciated that such ground angle may be determined utilizing geometry from the body angle and suspension length measurements although other calculation methods may be utilized as well. In particular, the processor 50 may calculate both the 387jair7gelinerUgged 2024-02-13

-10-ground slope (being the angle of the ground surface transverse to a longitudinal direction thereof) and the ground grade (being the angle of the ground along the longitudinal direction of the vehicle). In particular, the processor may determine the ground angle by either measuring the suspension angles at each side or front to rear of the vehicle or may alternatively calculate the suspension angle at each corner utilizing a differential between the cylinder lengths (as measured by position sensors within the cylinders). As illustrated in Figure 5, the body angle measurement 150 and the ground angle measurement 152 indicate the angle of the vehicle 10 and the ground surface 2 relative to horizontal respectively.
Using the calculated ground angles in step 104, the processor 10 then calculates a roll bias target 156 for the transverse direction (as illustrated in Figure 6) and pitch bias target (not illustrated) along the longitudinal direction of the vehicle 10. With reference to Figures 6 and 7, the roll bias target 156 represents a desired transverse angle 154 of the vehicle for a given side ground angle 152 wherein the roll bias target 156 represents an angular offset above the ground angle. A similar determination is made for the desired longitudinal pitch of the vehicle at the grade located under the vehicle 10.
It will be observed that the desired roll angle 154 may not be equal to the ground slope angle 152. In particular, the desired roll angle 154 may be determined according to a relationship that is non-linear such that the desired roll angle is less than and variable for each given slope angle 152 and is between the slope angle 152 and horizontal so as to increase at a rate less than the slop angle increase. With reference to Figure 8, the processor in step 106 may look up the roll bias target 156 in a table or chart defining the relationship of the roll bias angle 156 for each given ground roll angle. As illustrated, the relationship between the roll bias angle 156 and the ground roll angle 152 is not linear and may be selected to be of any relationship according to the preferences of a user.
In particular, the roll bias angle 156 may be follow a substantially non-linear relationship within a predefined central range 157 of horizontal ground roll angle.
Furthermore, the roll bias target may be determined as a ratio of the measured ground angle. Outside of these angle limits (generally indicated at 158), the roll bias angle 156 may be substantially linear. Within the central range 157, the 387ja I 74 8i 1/15"L'd4rUg d 2024-02-13

-11-relationship between the roll bias angle 156 and the ground roll angel 152 may be of any desirable relationship, including linear (at a ratio of less than 1:1), exponential, logarithmic, or segmented with multiple relationships provided the overall relationship is less than a 1:1 ratio thereby selecting a desired roll angle 154 that is less than the ground roll angle. Outside of the angle limit, the relationship may change to a substantially linear 1:1 ration between the desired roll angle 156 and the ground roll angle 152 due to the inability of the vehicle to continue reduce the roll of the vehicle 10 relative to the ground surface 2 beyond the limits of the suspension travel. The angle limits 158 are therefore chosen to reflect these limits beyond which roll reduction is not possible and will therefore depend on the geometry of the vehicle and the required remaining travel for the suspension components as will be further discussed below. The above description sets out the method for determining the roll bias angle 156. A
similar method may also be utilized for determining the pitch bias angle for the longitudinal direction of the vehicle. It will be appreciate that the relationships for the roll angle bias and the pitch angle bias may be the same or different depending on the user preferences.
With reference to Figure 5, in step 108, the processor 50 may calculate a suspension articulation bias target. In particular, the processor receives the measurement of the position of each cylinder 20 and calculates a measurement of the actual articulation of the vehicle. In particular the actual articulation bias is a measure of the difference in the transverse angle between the front and rear axels such as, by way of non-limiting example when one wheel of the vehicle is located on an obstacle so as to twist that axel relative to the longitudinal axis of the vehicle. Optionally, the system, including the processor 50 may include a filter configured to prevent a false measurement of the articulation due to the presence of temporary obstacle or sensor error. Examples of such filters may include but are not limited to a second-order butterworth filter, averaging filter or other known sensor filtering techniques. It will be appreciated that the measured actual articulation measurement may be represented as either an angle or a linear distance of offset of the height of the out of plane wheel by way of non-limiting example. In step 108, the processor 50 then utilizes the measured 387ja I gain er8a g d 2024-02-13

-12-articulation bias to determine a target articulation bias. In some embodiments the processor 50 may look up or obtain the target articulation bias from a chart or table.
In practice, the measured articulation bias will represent the measurement of the actual axel articulation of the vehicle 10 at that particular moment on the ground supporting the vehicle. By using this measurement to calculate a target articulation bias, a goal articulation angle for the vehicle 10 may be determined to which the suspension may be adjusted. With respect to a conventional vehicle, when the suspension is twisted longitudinally in an articulation state, two crosswise opposing suspension members will be compressed or loaded to a greater amount than the other two opposing suspension members. In such a conventional vehicle the crossed opposing load bearing members will remain in such a higher loaded state. Accordingly, the ground pressure asserted by the wheel at each cross wise opposing corner will remain higher than the other two wheels. For example, for a conventional vehicle crossing a ditch at an angle with the front right and real left corner on each side of the ditch with the front left and rear right corners above the middle of the ditch. In such positions, the front right and rear left corners would support a greater weight of the vehicle in relation to the spring rates of the suspension members. The front right and rear left corner tires would also exert a greater ground pressure. In extreme depths of ditches, one or both of the front left and rear right corner tires would be suspended in air with little or no ground contact. However, by contrast in the present system, by setting a target articulation bias close to the measured articulation bias, the suspension cylinders 20 may be adjusted to set a target unloaded position (as will be further discussed below) close to the measured articulation so as to have a substantially or close to neutral position at the present position of the vehicle. In such manner, the force or load carried by each of the suspension cylinders 20 will be substantially equal and accordingly the force applied by each of the wheels will be substantially equal or at least much close to equal as compared to a conventionally sprung vehicle. In such an adjusted spring position, ground loading by the wheels will be much more even allowing greater distribution of traction between the wheels and reduced 387jair7gelinerUgged 2024-02-13

-13-ground surface impact. Accordingly it may be appreciated that setting a target articulation bias close to the measured articulation bias may replication a longitudinally located joint in the vehicle adapted to set an articulation angle of the vehicle between the front and rear axels however such articulation angle is set by adjusting the cylinders 20 to be close to the measured articulation angle.
As illustrated in Figure 9, one exemplary chart of the measured against target articulation bias is illustrated. As shown in Figure 9, the target articulation bias may be reduced relative to the measured articulation bias from a 1 to 1 relationship generally indicated at 70. It will be appreciated that selecting a target articulation bias to be less than the measured articulation bias will provide an inclination to balance the system to a zero articulation state. Furthermore as illustrated in Figures 9 within a lower measured articulation bias value region generally indicated at 72 the target articulation bias may be further reduced relative to a 1 to 1 relationship. Such reduced target articulation bias at low articulation values may assist with reducing the responsiveness to the vehicle to smaller articulations values under the influence of small obstacles such as rocks, bumps and the like. It will be appreciated that reducing the responsiveness of the suspension system of the vehicle will provide a dampening of the impacts of relatively small disturbances while allowing larger measured articulations to be accommodated. It will also be observed that the target articulation may be set to a distance further from the measured articulation bias at larger angles. This may be set to correspond to angles which are approaching the articulation limits of the vehicle so as to reduce the effect of this target articulation bias on the overall suspension positioning and support of the vehicle 10.
Once the articulation bias target, pitch and roll bias targets are determined by the processor 50, a ride height target may be obtained in step 110 from either a user inputted value or alternatively from memory 52. Alternatively the ride height target may be determined based on the identification of any surrounding obstacles from the one or more scanners 68. The processor 50 then satisfies each of these values according to a predefined priority. In particular, according 387ja 174 8i 1/15"L'd4rUg d 2024-02-13

-14-to some embodiments, the processor may priority these factors in the following order, articulation bias target, roll bias target, pitch bias target and ride height. It will be appreciated that other priority orders may also be utilized. It will also be appreciated that one or more targets may be set to the same priority level such that the processor attempts to meet both targets simultaneously as best as is possible. Furthermore weighting may be applied to one or more targets so as to achieve that proportion of those targets relative to each other where it is not possible to meet all targets at that particular prioritization level. In particular, the processor 50 may determine suspension travel limits to achieve these prioritized targets in order of priority such as by way of non-limiting example, by ensuring that the top priority target is met, followed by subsequent targets until it becomes impossible to calculate a suspension travel. It will be appreciated that the processor 50 may utilize any known method of determining the permissible suspension travel limits in step 112 including, without limitation iterative calculations. Once the permissible travel limits are determined, the target corner height of each cylinder 20 may be calculated in Step 114.
The processor 50 as illustrated in step 116 is also configured to calculate the weight distribution on each of the corners of the vehicle 10. In particular, the processor 50 utilizes the suspension position measurements from step 102 to determine a substantially even weight distribution at each wheel. In particular, the processor 50 monitors the height of the suspension at each corner and compares that height to the average height for the vehicle along with the current pitch and roll. The processor 50 therefore monitors and determines if one or more of the cylinders 20 at a particular corner is determined to be longer or shorter than it should be for a partial vehicle orientation in which case, then determines that the short or high corner may be supporting too much, or too little of the total weight of the vehicle. As will be further set out below, the processor 50 can then direct the pumps 64 and valves 66 to increase or decrease the height of that cylinder until an even weight distribution is achieved through increasing the force applied by that cylinder as will be further set out below.
Alternatively, the weight distribution in step 116 may be disabled under one or more conditions including, without limitation vehicle speed over a predetermined 387ja I 74 8i1/15"L'd4rUg d 2024-02-13

-15-limit or cornering accelerations over a predetermined limit. It will be appreciated, that the weight distribution calculation in step 116 includes a consideration of the geometry of the vehicle due to the roll or pitch angle and therefore the downhill wheels in any weight description will result in a slightly greater weight load thereon due to the geometry of the vehicle including height of the center of gravity and angle of roll or pitch of the vehicle. The present weight distribution calculation will not attempt to even this slight imbalance but will account for it in determining the remaining height and therefore weight calculations.
Optionally, the processor 50 may also determine and adjust the stiffness (defined as a measure of the amount of suspension travel permitted under a given load) and balance this desired stiffness with the ride height orientation angles and weight distribution. As illustrated in Figure 5, the processor may receive at step 120 a stiffness target either as a user inputted field or from member 52. The processor 50 may then in step 118 calculate a stiffness target based on the natural frequency and weight of the vehicle which are known and based on the particular vehicle. In operation, the stiffness target may be variable depending on a selected driving mode from one or more options, speed of the vehicle and/or user preference.
In particular, the processor 50 may include one or more driving modes contained or otherwise stored in the memory 52, each having unique maps, charts or formulas dictating any of the above operating parameters including, without limitation target articulation bias, roll or pitch bias target, stiffness target or ride height target. It will be appreciated that each driving mode may correspond to a different road or driving condition including, on road, dirt road, off road, extreme obstacle or sensitive ground pressure location. The processor 50 may select between the different driving modes based on an input from a user which may be supplied either while stationary or while under movement, also referred to as "on the fly". Optionally, the processor 50 may be adapted to measure one or more inputs from a surrounding scanner 68 or biometric sensor 68 and change driving modes based on determinations made by the processor of the road type or ability level of one or more of the driver or passengers.
387ja I 748e 'apt er8a d 2024-02-13

-16-As set out above, the processor 50 is also configured to receive a pressure measurement from the one or more accumulators 41 and 43 in step 122. The processor 50 then uses the pressure within each accumulator 41 or 43 along with the pressure and position within it's connected cylinder by calculating fluid volumes in each of the accumulator and thereby to determine the gas volume in the accumulator defined as the pre-charge for that accumulator. The processor 50 utilizes this pre-charge along with the desired stiffness from step 118 and corner ride height targets in step 114 to calculate a target pressure within each accumulator in step 126. In particular, the processor 50 may perform an iterative process to solve for the pressures in each of the top and bottom accumulators to achieve the corner ride height targets, corner weight targets, suspension stiffness targets and accumulator pressures. It will be appreciated that such calculations are known for individual conditions of the pressure within the top and bottom of the cylinders 20 and accumulators as are known and dependant upon the specific cylinders and accumulators utilized. Such calculations will commonly represent the pressure and geometry calculations and responses of the particular actuators selected. It will be furthermore appreciated that although the embodiment illustrated utilizes hydrodynamic cylinders having a hydraulic cylinder and gas charged accumulator, other cylinder or suspension member types may also be utilized. In particular and by way of non-limiting example, pneumatic or electric actuators may be employed in place of the present cylinders 20 with the resulting specific calculations being adapted accordingly to represent the spring and/or dampening properties of the actuator.
Thereafter in step 128, the processor calculates the amount of fluid to be added to or vented from each accumulator and sends signals to the pumps and valves 64 and 66 to achieve such filling and venting changes in step 130. It will be appreciated that after such filling and venting the above process will be repeated continuously to adjust the orientation of the vehicle both in response to further adjusting that may be required as well as to adjust for a new position of the vehicle as it operated over varying terrain. It will be appreciated that all or 387ja I 74 8i1/15"L'd4rUg d 2024-02-13

-17-portions of the above control process may be employed by the processor depending on the needs of the vehicle 10. In particular, in some embodiments, the processor 50 may only determine the ride height targets without further calculating spring stiffness targets and adjust the height at each corner without adjusting the spring rates at each corner by way of non-limiting example.
In some further embodiments, the processor 50 may be adapted to modify the variables or adjustments made at least one of the operating conditions of the suspension or one of the above suspension control targets, including but not limited to target articulation bias, roll or pitch target, stiffness target or ride height target. In particular, the processor 50 may be adapted to modify one or more of these adjustments, including the charts utilized in steps 106 and 108 above in response to measurements within the vehicle of any one or more considerations, including, without limitation, ride harshness or impact, center of gravity changes or ground pressure calculations at each wheel.
According to further embodiments, the processor 50 may be operable to calculate and/or adjust the center of gravity of the vehicle 10 utilizing the pressures within the cylinders 20 and/or accumulators 43 and 41 to measure weight transfer front to back or side to side of the vehicle. In particular, the processor 50 may utilize the pressures and measured weight transfer along with known geometric properties to calculate or estimate the center of gravity or change in known center of gravity for the vehicle any payload contained therein.
While specific embodiments have been described and illustrated, such embodiments should be considered illustrative only and not as limiting the disclosure as construed in accordance with the accompanying claims.
387ja I gaii5H2ter8a d 2024-02-13

Claims (18)

What is claimed is:

1. A method for controlling the suspension of a vehicle, the vehicle having a body and a wheel proximate to each corner of the body suspended from the vehicle by a suspension assembly, the method comprising:
providing in each suspension assembly, a suspension actuator spanning between the wheel and the body;
measuring an angle of the body along at least one axis thereof relative to horizontal;
measuring an extension of each suspension actuator;
utilizing a processor:
determining an articulation target for the vehicle;
determining a body angle target for the vehicle;
determining a suspension actuator travel limit for each corner of the vehicle; and determining a ride height in each comer of the vehicle from a predetermined prioritization of a plurality of criteria comprising articulation target, body angle target and suspension actuator travel limit; and causing each suspension actuator to move to the determined ride height.

2. The method of claim 1 wherein the articulation target is looked up on a predefined chart or graph defining a predefined articulation bias.

3. The method of claim 2 wherein the predefined articulation bias is reduced relative to a 1 to 1 ratio within a predefined angle zero.

4. The method of claim 1 wherein each actuator comprises a cylinder including a piston therein defining a top chamber above the piston and a bottom chamber below the piston wherein the vehicle further includes a pressurized fluid source in selective communication with each of the top and bottom chambers.

5. The method of claim 4 further comprising adding or removing fluid from one or more top or bottom chamber of one or more pistons as determined by the processor.

6. The method of claim 1 further comprising:
determining a ready state of the each actuator;
receiving a desired suspension stiffness target; and utilizing the processor, calculating the actuator target states to provide the determined ride height and spring rates;

7. The method of claim 6 wherein the ready state comprises the pressure in one or more of the top and bottom chambers and accumulators of a suspension cylinder and adjusting pressure within each cylinder and/or accumulator to maintain achieve the desired ride height and suspension stiffness.

8. The method of claim 6 wherein the suspension stiffness target is variable.

9. The method of claim 1 wherein the prioritization comprises satisfying each criteria in a predefined order until satisfaction is not possible.

10. The method of claim 1 wherein the prioritization comprises satisfying each criteria in a predetermined ratio.

11. The method of claim 1 wherein the processor determines a measurement of the ground slope using the measure of the body angle and the measurement of each suspension actuator extension.

12. The method of claim 11 wherein the processor determines the body angle target from the ground slope.

13. A system for controlling body position of a vehicle comprising:
a suspension assembly at each corner of the vehicle having a suspension height actuator;
a processor in communication with each suspension height actuator;
and a memory containing instructions which when executed by the processor:
determine an articulation target for the vehicle;
determine a body angle target for the vehicle;
determine a suspension actuator travel limit for each corner of the vehicle; and determine a ride height in each corner of the vehicle from a predetermined prioritization of a plurality of criteria comprising articulation target, body angle target and suspension actuator travel limit; and causing each suspension height actuator to move to the determined ride height.

14. The system of claim 13 further comprising at least body angle sensor operable to transmit to the processor a measurement of the angle of the body along an axis relative to a horizontal plane.

15. The system of claim 13 further comprising a position sensor configured to measure the position of each suspension height actuator.

16. A suspension assembly for a vehicle comprising:
a wheel assembly located proximate to each corner of the vehicle;
a suspension actuator extending between each wheel assembly and the vehicle, the suspension actuator operable to support the vehicle thereon; and a processor operable to provide instructions to a valve assembly between the fluid source and each cylinder wherein the processor is configured to determine a desired vehicle body angle from a predetermined prioritization of body angle measurement, suspension articulation and ride height targets.

17. A method for controlling body position of a vehicle comprising measuring a current angle of the vehicle using a body angle sensor;
determining a distance of remaining compression at each of a suspension cylinder located at each corner of the vehicle;
identifying a cylinder located at an uphill location on the vehicle; and permitting the uphill cylinder to shorten until a remaining compression reaches a predetermined value or the current angle reaches a desired value.

18. A method of controlling a suspension of a vehicle comprising:
providing a cylinder at corner of the vehicle suspending a wheel assembly therefrom, wherein the cylinder includes a piston therein defining a top chamber having a top chamber defining a top spring constant and a bottom chamber having a bottom spring rate defining a bottom spring constant; and dynamically adding or removing fluid to one or more top or bottom cylinders so as to adjust one or more of spring rate, compression and rebound.